Dust seal structure of internal mixer

Abstract

A dust seal structure of an internal mixer including a casing having a mixing chamber defined therein, and a rotor rotating in the mixing chamber for kneading a material, which is charged into the mixing chamber to be kneaded there, comprises a ring-shaped cylinder fitted to a rotor shaft of the rotor and mounted on a peripheral edge of an opening portion of the casing through which the rotor shaft passes, the cylinder being located at the peripheral edge of the opening portion of the casing, and being adapted to urge a ring-shaped sealing member fitted on the rotor shaft in a direction of the rotor shaft to inhibit leakage of the kneading material from the mixing chamber.

1 . A dust seal structure of an internal mixer including a casing having a mixing chamber defined therein, and a rotor rotating in the mixing chamber for kneading a material, which is charged into the mixing chamber to be kneaded there,
 the dust seal structure comprising a ring-shaped cylinder fitted to a rotor shaft of the rotor and mounted on a peripheral edge of an opening portion of the casing through which the rotor shaft passes,   the pressing cylinder being located at the peripheral edge of the opening portion of the casing, and being adapted to urge a ring-shaped sealing member fitted on the rotor shaft in a direction of the rotor shaft to inhibit leakage of the kneading material from the mixing chamber.   
   
   
       2 . The dust seal structure of an internal mixer according to  claim 1 , wherein
 the sealing member has sealing surfaces making close contact with and internally fitted on a peripheral surface of the opening portion of the casing and abutting on an end surface of the rotor.   
   
   
       3 . The dust seal structure of an internal mixer according to  claim 2 , wherein
 the sealing member is urged by the cylinder via a ring-shaped press fitting movable within the opening portion of the casing in the direction of the rotor shaft.   
   
   
       4 . The dust seal structure of an internal mixer according to  claim 1 , wherein the sealing member comprises
 a rotating sealing member fixedly provided on the rotor shaft and having a sealing surface on a side opposing an end surface of the rotor, and   a fixed sealing member connected to the cylinder and urged toward a shaft end of the rotor shaft, and having a sealing surface in contact with the sealing surface of the rotating sealing member, and a tubular portion in sliding contact with a peripheral surface of the opening portion of the casing, and   the sealing member seals a gap between an outer peripheral surface side of the rotor shaft and an inner peripheral surface of the tubular portion.   
   
   
       5 . The dust seal structure of an internal mixer according to  claim 4 , wherein
 the rotating sealing member is fixedly provided on a sleeve which is inserted into the tubular portion of the fixed sealing member and fitted on the rotor shaft.   
   
   
       6 . The dust seal structure of an internal mixer according to  claim 1 , wherein
 the cylinder is a hydraulic cylinder.   
   
   
       7 . The dust seal structure of an internal mixer according to  claim 1 , wherein
 the cylinder is a pneumatic suspension cylinder.   
   
   
       8 . The dust seal structure of an internal mixer according to  claim 1 , wherein
 the cylinder is formed to be divisible into a plurality of segments in a circumferential direction of the rotor shaft, and   has piston portions accommodated in one or more cylinder chambers defined independently of each other in the segments.